Xinhua News Agency, citing the local government, said 10 more people were injured, four of them critically, in the incident Sunday during an event in honor of a late religious figure at the mosque in Ningxia's Xiji Town.
The injured were hospitalized and authorities ordered an investigation into the incident, Xinhua said.
Chinahighlights.com, a China-based tour operator, says the Hui ethnic group is among various Muslims groups inhabiting the Ningxia-Hui region with a population of about 9.8 million.
Among other Muslim minorities in China's are Uighurs who are mostly in northwestern China's Xinjiang region, which has been the scene of violent ethnic tensions lately, resulting in the deaths of dozens of people.
2014: The Year in Music [PHOTOS]